How Domain Validation Works

The domain validation process is elegantly simple, focusing solely on verifying that the applicant has control over the domain for which they're requesting the certificate. Certificate Authorities use several automated methods to perform this verification, each designed to prove domain control without requiring human intervention. The most common validation methods include email validation, where the CA sends a verification email to predetermined addresses like [email protected] or [email protected]. The applicant simply clicks a link or enters a code from this email to complete validation.

DNS validation offers another popular method, particularly favored by technical users and automated systems. This process requires the applicant to add a specific TXT record to their domain's DNS settings. The CA then queries the DNS to verify the presence of this record, confirming domain control. File-based validation provides a third option, where applicants upload a specific file to their web server at a predetermined location. The CA's automated systems then attempt to retrieve this file, confirming that the applicant controls the web server associated with the domain.